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Bench Mark Sheet for 9457493, SW Terror Bay AK

Superseded Epoch

Large map location marker Station Location
Small red map location marker Published bench mark
Small blue map location marker Unpublished bench mark

Bench mark positions only appear on the map if their coordinates in the CO-OPS database are at the precision of degrees/minutes/seconds/and tenths of seconds. If the coordinates are less precise, the mark will not appear.

Printable version

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  5

                                                                                
Station ID: 9457493                         PUBLICATION DATE:  12/30/2014
Name:       SW TERROR BAY                                     
            AK
NOAA Chart: 16597                           Latitude:   57° 44.6' N (  57.74403)
USGS Quad:  KODIAK (c-4), ALASKA            Longitude: 153° 11.7' W (-153.19547)


To reach the tidal bench marks from Port Lions, AK by boat, start at the
entrance to Settler Cove at position 57 52.64  N, 152 50.18  W, and proceed in
Kizhuyak Bay on course 050 T for 2.5 nautical miles (NM) to 57 54.26  N, 152
46.55  W, then proceed through Whale Passage on course 312  T for 3.0NM to 57
56.24  N, 152 50.74  W, where Pokati Point will be abeam to port.  Continue
through Kupreanof Strait on course 291  T for 15.5NM to 58 01.77  N, 153 18.13 
W with Outlet Cape abeam to port, then turn to port to course 200 T for 4.9NM,
exiting Kupreanof Strait, entering Viekoda Bay, to 57 57.17  N, 153 21.35  W.
Alter course to 130 T for 3.4NM to position 57 54.95  N, 153  16.40  W and then
proceed on course 155 T entering East Uginik Passage for 5.1NM to position 57
50.37  N, 153 12.31  W.   Alter to course 172 T for 2.0NM to continue through
East Uginik Passage.  Continue south on course 180 T for 2.5NM past the entrance
to Uganik Passage and in to Terror Bay. Finally, proceed on course 198  T for
2.3NM to the end of Terror Bay  where the benchmarks are located along the rocky
shore


                         T I D A L   B E N C H   M A R K S


                 PRIMARY BENCH MARK STAMPING:  7493 C 2014
                         DESIGNATION:          945 7493 C

MONUMENTATION:           Bench Mark disk                       VM#:        21295
AGENCY:                  National Ocean Service                IDB PID#:        
SETTING CLASSIFICATION:  Bedrock outcrop                       OPUS PID#: BBDR11
LATITUDE:   57° 43.9' N (  57.73167)          LONGITUDE: 153° 13.4' W (-153.22306)


The primary bench mark is a disk set flush in bedrock 3m (9.9ft) in front of an
8m (26.3ft) vertical face. However, direct line of sight is blocked by a bedrock
outcrop directly N. When on the mark, the highest point on the E shore   2410ft
peak charted at 57 44.55 N, 153 10.17 W   bears 088 T (072 M).

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  5

                                                                                
Station ID: 9457493                         PUBLICATION DATE:  12/30/2014
Name:       SW TERROR BAY                                     
            AK
NOAA Chart: 16597                           Latitude:   57° 44.6' N (  57.74403)
USGS Quad:  KODIAK (c-4), ALASKA            Longitude: 153° 11.7' W (-153.19547)


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  7493 A 2014
                         DESIGNATION:          945 7493 A

MONUMENTATION:           Bench Mark disk                       VM#:        21293
AGENCY:                  National Ocean Service                IDB PID#:        
SETTING CLASSIFICATION:  Bedrock outcrop                       OPUS PID:        
LATITUDE:   57° 43.9' N (  57.73111)          LONGITUDE: 153° 13.4' W (-153.22306)


The bench mark is a disk set vertically in the middle of series jagged bedrock
outcroppings facing 026 T (010 M) at the 2823ft peak located at 57 49.81 N, 153
06.62 W, S of the small stream bisecting a small rocky beach (charted on 16597
as the northernmost stream on the west bank of Terror Bay).



                         BENCH MARK STAMPING:  7493 B 2014
                         DESIGNATION:          945 7493 B

MONUMENTATION:           Bench Mark disk                       VM#:        21294
AGENCY:                  National Ocean Service                IDB PID#:        
SETTING CLASSIFICATION:  Bedrock outcrop                       OPUS PID:        
LATITUDE:   57° 43.9' N (  57.73167)          LONGITUDE: 153° 13.4' W (-153.22333)


The bench mark is a disk set flush in bedrock 4m (13.1 ft) in front of a 16m
(52.5 ft) vertical face, N of the small stream bisecting a small rocky beach
(charted on 16597 as the N most stream on the W bank of Terror Bay). However
direct line of sight is blocked by a bedrock outcropping.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  5

                                                                                
Station ID: 9457493                         PUBLICATION DATE:  12/30/2014
Name:       SW TERROR BAY                                     
            AK
NOAA Chart: 16597                           Latitude:   57° 44.6' N (  57.74403)
USGS Quad:  KODIAK (c-4), ALASKA            Longitude: 153° 11.7' W (-153.19547)


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  7493 D 2014
                         DESIGNATION:          945 7493 D

MONUMENTATION:           Bench Mark disk                       VM#:        21296
AGENCY:                  National Ocean Service                IDB PID#:        
SETTING CLASSIFICATION:  Bedrock outcrop                       OPUS PID:        
LATITUDE:   57° 43.9' N (  57.73194)          LONGITUDE: 153° 13.4' W (-153.22306)


The bench mark is a disk set flush in bedrock outcropping. Vegetation is low on
the rock face behind 945 7493 D. When on the mark, the highest point on the E
shore   2410ft peak charted at 57 44.55 N, 153 10.17 W   bears 088 T (072 M).
The prominent point on the W shore of Terror Bay towards the mudflats bears 150
T (134 M). The 2823ft peak charted at 57 49.82 N, 153 06.81 W bears 048 T (032
M) 



                         BENCH MARK STAMPING:  7493 E 2014
                         DESIGNATION:          945 7493 E

MONUMENTATION:           Bench Mark disk                       VM#:        21297
AGENCY:                  National Ocean Service                IDB PID#:        
SETTING CLASSIFICATION:  Bedrock outcrop                       OPUS PID:        
LATITUDE:   57° 43.9' N (  57.73222)          LONGITUDE: 153° 13.4' W (-153.22278)


The bench mark is a disk set flush in bedrock 3m (9.9ft) in front of an 8m
(26.3ft) vertical face. When on the mark, the highest point on the E shore  
2410ft peak charted at 57 44.55 N, 153 10.17 W    bears 088 T (072 M). The
prominent point on the W shore of Terror Bay towards the mudflats bears 154 T
(138 M). 

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  5

                                                                                
Station ID: 9457493                         PUBLICATION DATE:  12/30/2014
Name:       SW TERROR BAY                                     
            AK
NOAA Chart: 16597                           Latitude:   57° 44.6' N (  57.74403)
USGS Quad:  KODIAK (c-4), ALASKA            Longitude: 153° 11.7' W (-153.19547)


                            T I D A L   D A T U M S 


Tidal datums at SW TERROR BAY based on:

     LENGTH OF SERIES:      1 MONTH
     TIME PERIOD:           September 2014 - September 2014
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  9457804 ALITAK,  LAZY BAY


Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:

     MEAN HIGHER HIGH WATER                     MHHW   =  4.313
     MEAN HIGH WATER                            MHW    =  4.038
     MEAN TIDE LEVEL                            MTL    =  2.270
     MEAN SEA LEVEL                             MSL    =  2.253
     MEAN LOW WATER                             MLW    =  0.503
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     7493 C 2014                                 3.926   -0.112
     7493 A 2014                                 5.335    1.297
     7493 B 2014                                 4.688    0.650
     7493 D 2014                                 4.514    0.476
     7493 E 2014                                 4.527    0.489


                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  5

                                                                                
Station ID: 9457493                         PUBLICATION DATE:  12/30/2014
Name:       SW TERROR BAY                                     
            AK
NOAA Chart: 16597                           Latitude:   57° 44.6' N (  57.74403)
USGS Quad:  KODIAK (c-4), ALASKA            Longitude: 153° 11.7' W (-153.19547)


                             D E F I N I T I O N S


Mean Sea Level (MSL) is a tidal datum determined over a 19-year National Tidal
Datum Epoch.  It pertains to local mean sea level and should not be confused
with the fixed datums of North American Vertical Datum of 1988 (NAVD88).

NAVD88 is a fixed datum derived from a simultaneous, least squares, minimum
constraint adjustment of Canadian/Mexican/United States leveling observations.
Local mean sea level observed at Father Point/Rimouski, Canada was held fixed as
the single initial constraint.  NAVD88 replaces NGVD29 as the national
standard geodetic reference for heights.  Bench mark elevations relative to
NAVD88 are available from NGS through the World Wide Web at 
National Geodetic Survey.

NGVD29 is a fixed datum adopted as a national standard geodetic reference for
heights but is now considered superseded.  NGVD29 is sometimes referred to as
Sea Level Datum of 1929 or as Mean Sea Level on some early issues of Geological
Survey Topographic Quads.  NGVD29 was originally derived from a general
adjustment of the first-order leveling networks of the U.S. and Canada after
holding mean sea level observed at 26 long term tide stations as fixed.
Numerous local and wide-spread adjustments have been made since establishment in
1929.  Bench mark elevations relative to NGVD29 are available from the National
Geodetic Survey (NGS) data base via the World Wide Web at 
National Geodetic Survey.

NAVD88 and NGVD29 are fixed geodetic datums whose elevation relationships to
local MSL and other tidal datums may not be consistent from one location to
another.

The Vertical Mark Number (VM#) and PID# shown on the bench mark sheet are unique
identifiers for bench marks in the tidal and geodetic databases, respectively.
Each bench mark in either database has a single, unique VM# and/or PID# assigned.
Where both VM# and PID# are indicated, both tidal and geodetic elevations are
available for the bench mark listed. The NGS's Integrated Data Base (IDB PID)
provides geodetic datum based on traditionally leveled and bluebooked ties to
the National Spatial Reference System(NSRS) https://www.ngs.noaa.gov/datasheets/.
The NGS Online Positioning User Service (OPUS PID) provides geodetic datum based
on GPS position & tie it to the NSRS https://www.ngs.noaa.gov/OPUS/.

The NAVD88 elevation is shown on the Elevations of Tidal Datums Table Referred
to MLLW only when two or more of the bench marks listed have NAVD88 elevations.
The NAVD88 elevation relationship shown in the table is derived from an average
of several bench mark elevations relative to tide station datum.  As a result of
this averaging, NAVD88 bench mark elevations computed indirectly from the tidal
datums elevation table may differ slightly from NAVD88 elevations listed for
each bench mark in the NGS database.

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Products available at 9457493 SW Terror Bay, AK

Revised: 08/08/2018
NOAA / National Ocean Service
Web site owner: Center for Operational Oceanographic Products and Services